Acute diarrhea causes considerable global morbidity and is a common presenting symptom
in general practice in the United States [1]. Infection is the most common cause of
acute diarrhea, and is related to environmental conditions including close living
and working conditions, globalization of food production, contaminated food and water
supplies, and inadequate sewage disposal [2].
Epidemiology
Diarrheal diseases are the second most common cause of death worldwide and the leading
cause of childhood deaths [3], [4]. In Great Britain, a prospective study followed
8000 adults over 4 months. Eight percent of adults reported one episode of diarrhea
during the previous month, resulting in an estimate of one episode of acute diarrhea
per person per year [5]. Mortality from diarrhea is usually related to dehydration
and greatest in the elderly and children living in developing countries [6], [7].
Severe acute diarrhea is more prevalent in vulnerable populations including travelers;
the elderly; adults exposed to children; homosexual men; and individuals immunosuppressed
by HIV infection, chronic steroids, or chemotherapy [8], [9].
Definitions
The average stool output for men is 100 g of stool per day [10], [11], [12]. Objectively,
diarrhea is defined as stool weight greater than 200 g in 24 hours [12]. Clinically,
diarrhea is a change in stools, usually defined as passage of three or more loose
or watery stools or one or more bloody stool in 24 hours [8]. Acute diarrhea lasts
less than 14 days, whereas diarrhea lasting more than 14 days is termed “persistent
diarrhea,” and longer than 1 month is termed “chronic” [12]. Severe acute diarrhea
warrants immediate medical evaluation and hospitalization. The criteria for severe
acute diarrhea include volume depletion, fever, six or more stools in 24 hours, an
illness lasting longer than 48 hours, significant abdominal pain in individuals over
50 years, and immunocompromised patients [8], [13].
History
Important clinical history includes the onset of illness, duration of symptoms, weight
loss, presence of nocturnal diarrhea, and whether contacts are sick. It is also important
to quantify and characterize the stools and the bloody stools.
Clues to the etiology of diarrhea can be obtained through a detailed history regarding
travel to an endemic area; exposure to untreated water; medication use (particularly
laxatives or antibiotics); and sexual preference. Additional helpful history includes
occupational exposures, such as veterinarians, food handlers, and day care center
workers [12], [13], [14], [15], [16], [17].
Although dietary history is notoriously inaccurate, foods suspiciously linked to foodborne
diarrheal illness are unpasteurized dairy products, undercooked meat, and fish. The
timing of diarrheal symptoms with suspected recent food ingestion is also helpful
[18].
Diarrhea may be associated with other gastrointestinal symptoms including nausea,
vomiting, abdominal pain, fever, fecal urgency, and tenesmus. Volume status can be
assessed from questions focusing on thirst, urination, dizziness, and syncope [8],
[9].
Physical examination
To assess the severity of acute diarrhea, physical examination should focus on signs
of moderate or severe dehydration and signs of systemic toxicity. Extracellular volume
can be assessed by vital sign abnormalities including fever, tachycardia, and postural
hypotension [19]. Other physical examination findings of dehydration include assessment
of jugular venous pressure, skin turgor, mucosal membranes, and capillary refill [20].
The presence of peritoneal signs on examination may suggest an infection with an invasive
enteric pathogen, or an etiology requiring urgent surgical evaluation and management
[9]. A rectal examination should be performed in all patients presenting with acute
diarrhea, but especially in patients over the age of 50. The rectal examination helps
the physician assess stool character, type of diarrhea, and presence of blood [21].
Laboratory evaluation
The frequency of isolating an organism from a stool culture in infectious diarrhea
ranges from 2% to 40%, reflecting different populations undergoing testing, extent
of testing performed by primary care providers, and the persistence of pathogens in
stool [5], [22], [23], [24], [25]. The prevalence of identifiable infectious agents
is underestimated because many patients do not seek medical attention for acute diarrhea
and testing is not always performed. In one study, 22% of patients with gastroenteritis
consulted a physician and only 5% submitted a stool sample [26]. Another study analyzed
1783 surveys from United States physicians assessing patients with acute diarrhea
in the previous year to evaluate factors influencing their decision to obtain stool
cultures. Stool cultures were requested from 79% of patients with a history of bloody
stools, 40% of patients with nonbloody stools, and 53% of patients with diarrhea for
longer than 3 days. Patients with AIDS, fever, or a history of recent travel were
also more likely to have stool cultures performed [27].
Stool studies
Indications for stool studies in acute diarrhea are fever, bloody diarrhea, history
of travel to an endemic area, an acute flare of inflammatory bowel disease, recent
antibiotics, immunosuppression, employees involved in food handling, exposure to infants
in day care centers, and history of anal intercourse [28]. One may need to notify
the laboratory if special media, stains, or processing of the specimen is needed.
Fecal leukocyte, lactoferrin, and occult blood are often present in patients with
diarrhea and diffuse colonic inflammation [29], [30]. These tests are most helpful
in febrile patients with moderate to severe acute infectious diarrhea because when
positive, they lend support toward using empiric antimicrobial therapy, and when negative
may eliminate the need for stool cultures [31].
Stool samples sent for culture should be fresh, within 2 hours after passage if possible,
to allow best detection of organisms that decompose easily [32]. If stool samples
are not available, a rectal swab can be placed in transport media and then cultured
[8]. Stool studies are often inappropriately ordered [23]. Evaluation for ova and
parasites is not cost effective in severe acute diarrhea [25].
Flexible sigmoidoscopy or colonoscopy
Flexible sigmoidoscopy and colonoscopy are indicated in some cases of severe diarrhea
to evaluate colitis, distinguish between infection and inflammatory bowel disease,
and look for pseudomembranes or signs of ischemia [33], [34], [35].
Differential diagnosis of severe acute diarrhea
Infections
Infections are the most common cause of acute diarrhea. Viruses account for 50% to
70% of acute infectious diarrhea, bacteria 15% to 20%, parasites 10% to 15%, and 5%
to 10% of acute infectious diarrhea is of unknown etiology [8]. The following discussion
focuses on common causes of severe acute diarrhea.
Vibrio cholerae and noncholera vibrios
Vibrio cholerae is a gram-negative curved rod that adheres to small bowel epithelial
cells, releases an enterotoxin, and causes a small bowel diarrheal illness [36]. Between
1995 and 2000, 61 cases of V cholerae 01 were reported in the United States. Foreign
travel and undercooked seafood harvested from the Gulf Coast account for most cases
of cholera in the United States [37]. Noncholera vibrios, such as V parahemolyticus,
also occur on coastal areas of the United States where contaminated shellfish may
transmit disease and cause diarrhea. An outbreak of V parahemolyticus recently occurred
in three states and was associated with shellfish harvested from the Long Island Sound
[38].
Severe profuse watery diarrhea with prominent dehydration in an endemic area is usually
caused by V cholerae serogroup 01. Other features are abrupt onset of illness and
absence of blood or fecal leukocytes on stool examination [39]. Stools have a “rice
water” appearance with little food residue. A history of gastric surgery and use of
proton pump inhibitors or H2 receptor blockers that decrease gastric acid increase
susceptibility to cholera because more organisms survive transit [40]. Non-01 cholera
vibrios produce several toxins and cause a wide range of illness, including watery
diarrhea, dysentery, wound infections, and bacteremia [41]. V vulnificus can be fatal
in patients with underlying liver disease [42].
In endemic areas during outbreaks or seasonal epidemics of cholera, watery diarrhea
of all severity should be treated as cholera and stool culture done for confirmation.
Darkfield microscopy can best identify organisms that classically are motile “shooting”
bacteria [43]. Stool culture best detects the pathogen if performed on thiosulfate-citrate-bile-salts-sucrose
agar [44]. Further identification of Vibrio species requires serotyping and serogrouping
[41].
Treatment of V cholerae and noncholera vibrios rests on supportive measures including
fluid and electrolyte replacement to decrease mortality [45]. Monitoring stool volume
aids in the calculation of fluid deficits. In moderate to severe diarrhea, at least
half of the calculated deficit should be replaced in the first 4 hours, and the remainder
over the next 24 hours. Antibiotics decrease stool volume and shorten the clinical
course of the diarrheal illness. When stool culture sensitivities are unknown, empiric
treatment with tetracycline, doxycycline, or a fluoroquinolone can be administered
[46].
Campylobacter jejuni
Approximately 2.4 million cases of Campylobacter occur in the United States, making
it the most common cause of bacterial gastroenteritis [47]. It is acquired from ingestion
of undercooked contaminated poultry and resembles Salmonella in that an animal (usually
poultry) is the reservoir for human infection [48]. Campylobacter causes ileocolitis
with either watery or hemorrhagic diarrhea. Campylobacter has also been causally linked
to development of postinfectious reactive arthritis and Guillain-Barré syndrome [49],
[50], [51].
Stool culture more accurately identifies Campylobacter if microaerophilic cultivation
with inhibitory media is performed on the specimen [52]. Culture-proved severe Campylobacter
can be treated with antibiotics, such as erythromycin or fluoroquinolones, to shorten
the illness. Worldwide resistance is increasing and commonly occurs during therapy;
it is important to confirm in vitro susceptibility [53], [54], [55], [56].
Nontyphoidal Salmonella
Salmonellosis is one of the leading causes of foodborne disease in the United States.
Nontyphoid salmonellosis occurs in approximately 1.4 million people in the United
States each year, commonly during the summer and fall, and is associated with ingestion
of contaminated poultry, eggs, and milk products [21], [57]. Initially salmonellosis
may present as a small bowel diarrhea, but often progresses to colitis [9].
Bacteremia occurs in 2% to 14%, especially in infants and the elderly [58], [59],
[60]. Other risk factors for developing bacteremia from intestinal salmonellosis include
immunosuppression, uremia, hemolytic anemia including sickle cell anemia, and malignancy
[61], [62], [63], [64], [65], [66], [67].
Routine stool culture accurately identifies most salmonella. Treatment for nontyphoidal
Salmonella is controversial because of increasing antibiotic resistance and because
studies have not conclusively shown a difference in duration of illness or diarrhea
in patients treated with antibiotics versus placebo [68]. In high-risk patients at
risk for bacteremia, however, antimicrobial therapy is recommended with trimethoprim
sulfasoxazole (TMP/SMX) or a fluoroquinolone [69].
Shigella
Shigella is another commonly documented foodborne disease, accounting for 10% to 20%
of all cases of diarrhea in the United States [27]. As few as 200 organisms can initiate
the disease [70]. Most transmission is through person-to-person contact, contributing
to epidemics in day care centers and institutional settings. Shigella infection causes
exudative colonic hemorrhagic diarrhea and may be complicated by the development of
hemolytic uremic syndrome (HUS); thrombocytopenic purpura; and other extraintestinal
complications, such as arthritis [71], [72], [73].
Stool culture more accurately identifies Shigella if performed on xylose-lysine-desoxycholate
or Salmonella-Shigella agar [74]. Antimicrobial therapy shortens the duration of illness
[75], [76]. If shigella is acquired in the United States, recommended treatment is
TMP-SMX. If acquired abroad, a quinolone is generally recommended because TMP resistance
is common [46].
Yersinia enterocolitica
Yersinia enterocolitica causes hemorrhagic diarrhea and severe abdominal pain that
can mimic appendicitis [77]. Epidemics have been associated with contaminated milk.
Transmission to humans from domestic and farm animals has also been described [78].
Stool culture more accurately identifies Y enterocolitica if it is sent for cold enrichment
or Yersinia-selective agar [79]. For severe cases of yersiniosis, treat with a fluoroquinolone
or ceftriaxone [80].
Clostridium difficile
Clostridium difficile should be suspected in patients with a history of antibiotics
within 2 months of the onset of diarrhea, and in hospitalized patients developing
diarrhea at least 72 hours after admission [81]. The overall incidence of C difficile
in hospitalized patients is 28% and increases in the elderly [82], [83], [84].
Antibiotics change the normal intestinal flora, leading to increased proliferation
of C difficile producing enterotoxin A and B, resulting in colitis and pseudomembranes
[85]. Common antibiotics predisposing to C difficile infection are clindamycin, ampicillin,
and cephalosporins [86]. Patients may develop fever, abdominal cramping, and leukocytosis.
Typically, diarrhea is initially watery and voluminous with no gross blood or mucus,
but in severe cases can progress to bloody diarrhea. Dehydration is mild except in
very severe cases. Severe cases can have toxic megacolon or rarely perforation and
death [85], [87], [88].
Stool examination reveals numerous red blood cells and fecal leukocytes. Stool culture
for C difficile ideally needs anaerobic conditions. A positive stool culture does
not distinguish disease from carriers. Diagnosis of disease rests on detection of
toxin in the stool. Tissue culture is the gold standard but most laboratories use
rapid enzyme immunoassay tests for toxin A or B or both, now giving way to ELISA tests
[89], [90]. Sigmoidoscopy or colonoscopy can be performed if immediate diagnosis of
colitis is needed, and can show minimally erythematous colonic mucosa with edema,
or granular, friable, or hemorrhagic mucosa with pseudomembranes [91].
Treatment for C difficile includes correction of dehydration, stopping antibiotics
if possible, and metronidazole [92]. In severe cases, or in those who cannot take
metronidazole, vancomycin is an alternative [93]. Relapse occurs in approximately
20% of treated patients [94], [95], [96].
Enterohemorrhagic Escherichia coli diarrhea
Enterohemorrhagic Escherichia coli, especially E coli 0157:H7, can cause colitis [97].
Ingestion of undercooked ground beef has been most commonly implicated; however, many
other food vehicles have been reported. Patients frequently have abdominal pain and
hemorrhagic diarrhea. The most worrisome complications are HUS and thrombocytopenic
purpura, which are more common in children [98], [99], [100].
Suspected enterohemorrhagic E coli should be cultured on sorbitol-MacConkey agar [101].
The Centers for Disease Control and Prevention recommends screening stool from all
patients with a history of bloody diarrhea for E coli O157:H7 or Shiga toxin by direct
stool examination and confirmation by a reference laboratory if positive.
Antimicrobial therapy is controversial when E coli O157:H7 and other Shiga toxin producing
E coli are suspected [8]. Studies examining the administration of antibiotics during
early infection concluded there might be increased toxin release from killed organisms
leading to greater absorption and increased likelihood of developing HUS [102], [103],
[104]. In a prospective study, however, treatment with TMP-SMX late in illness did
not predispose to HUS [105]. Conflicting data have led to uncertainty regarding antibiotic
treatment for this pathogen. Current recommendations suggest supportive treatment,
monitoring for microangiopathic complications of HUS, and avoiding antibiotics especially
in children with diarrhea.
Viruses
Viruses commonly cause diarrhea but it is rarely severe [106]. Norwalk virus, Rotavirus,
Astrovirus, Calicivirus, Coronavirus, Enterovirus, and enteric adenovirus (type 40,41)
are waterborne or foodborne illnesses with an incubation period of 1 to 3 days. Associated
symptoms are abrupt onset of nausea and abdominal cramps followed by vomiting or diarrhea.
Fevers occur in approximately 50% of affected individuals. Headache, myalgias, upper
respiratory symptoms, and abdominal pain are common. Stool studies are negative for
fecal leukocytes and blood. The illness is usually mild and lasts 1 or 2 days. Oral
fluids are generally suggested; intravenous fluids are only needed in rare cases [107].
Bismuth subsalicylate can improve clinical symptoms of viral gastroenteritis [108].
Protozoa and parasites
Protozoa that may cause acute diarrhea include the colonic pathogen Entamoeba histolytica,
and small intestine pathogens Giardia lamblia, Isospora, Cyclospora, Microsporidium,
and Cryptosporidium. Infection may occur from travel to endemic areas and contact
with contaminated food, water, or another infected individual. For example, a Cyclospora
cayetanensis outbreak occurred from ingestion of raspberries from Guatemala [109].
Immunocompromised patients are most vulnerable to infection with these organisms.
The laboratory should be advised of specific organisms that are being considered to
improve the sensitivity of detection. Treatment is aimed at the specific organism.
Special cases
Immunocompromised individuals
Diarrhea has been reported in up to 60% of patients with AIDS in industrialized countries
and in 95% of patients with AIDS in the developing world [110]. Organisms causing
diarrhea in patients not on antiretroviral therapy are numerous and include Cryptosporidium
parvum, Isospora belli, Cyclospora, Microsporidia, G lamblia, Strongyloides, E histolytica,
Salmonella enteritidis, Campylobacter, Shigella, Mycobacterium avium, cytomegalovirus,
herpes simplex, Epstein-Barr virus, adenovirus, tuberculosis, and mycobacterium avium
complex [111], [112], [113]. A full discussion of the pathogens commonly causing acute
diarrhea in patients immunocompromised from AIDS, cancer chemotherapy, and bone marrow
transplant is beyond the scope of this article. The treatment of diarrhea in immunocompromised
patients is essentially the same as normal hosts, but may require prolonged courses
of antimicrobial therapy. Patients with advanced immunocompromise (absolute CD4 count
less than 200 cells/mm3) should have stool studies and start empiric treatment with
a quinolone for bacterial sources of infection [113].
Noninfectious causes
There are important noninfectious causes of severe acute diarrhea. Inflammatory bowel
disease can occasionally have an acute onset. This is more common with ulcerative
colitis but can be seen with Crohn's disease. Symptoms include diarrhea with mucus,
rectal bleeding, and abdominal pain. Young adults between the ages of 20 and 40 are
typically affected but the elderly can also have inflammatory bowel disease. The diagnosis
of ulcerative colitis relies on clinical history, stool studies to exclude infection,
and either sigmoidoscopy or colonoscopy to document the extent of disease. Plain films
can also provide information regarding the extent of disease and can diagnose the
complication of toxic colon [114]. Medical management of ulcerative colitis includes
glucocorticoids, aminosalicylates, and immunosuppressive agents including azathioprine
and 6-mercaptopurine [115]. Colectomy is reserved for patients with severe attacks
who fail to respond to medical treatment, complications of a severe attack, dysplasia,
or carcinoma [116].
Medications may also cause acute diarrhea. The most common medications responsible
for acute diarrhea are laxatives; antacids containing calcium or magnesium; colchicine;
antibiotics; sorbitol gums; and enteral tube feeds, especially if hypertonic. Diarrhea
usually resolves after cessation of the medication [117].
Acute radiation enteritis may occur within hours to 3 weeks after treatment. The severity
of the enteritis depends on the size of the radiation field, total dose of radiation
received, and concurrent chemotherapy. Patients clinically have nausea, diarrhea,
and abdominal cramps and nausea from increased intestinal motility, and decreased
surface epithelium for absorption. The terminal ileum is frequently irradiated during
treatment of pelvic malignancies; steatorrhea, decreased absorption of vitamin B12,
and bile acids may occur. Diarrhea generally resolves within 2 to 6 weeks after completion
of radiation [118].
Intestinal ischemia should be considered in patients who have had an episode of hypotension
or shock and subsequently develop bloody diarrhea from ischemic colitis, or profound
diarrhea from small bowel ischemia. The elderly, patients with a history of hypercoagulable
states, congestive heart failure, cardiac arrhythmias, recent myocardial infarction,
unexplained abdominal distention, or gastrointestinal bleeding should also be evaluated
for intestinal ischemia, and surgical consultation obtained for possible resection
[34], [119].
Management of severe acute diarrhea
Medical management of severe acute diarrhea includes fluid rehydration, electrolyte
replacement, diet alteration, antimicrobial treatment, and symptomatic therapy (Fig.
1
) [120].
Fig. 1
Algorithm developed for the management of adult diarrhea. (1) Stool examination and
culture methods depend on availability, affordability, and local practice of each
community or country. (2) Strongly recommended for severely ill patients (select antibiotics
according to sensitivity of local antibiogram). ATB, antibiotics; DFM, darkfield microscopy
(if not available, look for “shooting bacteria” under light microscopy); EHEC, enterohemorrhagic
E coli; IVF, intravenous fluid; ORT, oral rehydration therapy. (Adapted from Manatsathit
S, Dupont HL, Farthing M, et al. Guideline for the management of acute diarrhea in
adults. J Gastroenterol Hepatol 2002;17:S54–71; with permission.)
Fluids
Fluids used for rehydration should contain sodium, potassium, and glucose [121], [122],
[123]. Oral rehydration solutions were developed following the realization that in
many small bowel diarrheal illnesses the intestine can still absorb water if glucose
and salt are present to assist in the transport of water from the intestinal lumen.
The oral rehydration solution recommended by the World Health Organization consists
of 3.5 g sodium chloride, 2.5 g sodium bicarbonate, 1.5 g KCl, 20 g of the mixture
in 1L of clean drinking water.
Intravenous fluid therapy is essential treatment in severely dehydrated patients who
are hypovolemic, in shock, or who cannot tolerate oral rehydration therapy because
of severe vomiting or altered mental status [9]. Ringer's lactate is recommended for
adults. It is recommended that one calculate the total fluid deficit in severely dehydrated
patients; give half within the first hour then the rest over next 3 hours [124]. The
volume of fluid is based on rate of stool losses and degree of pre-existing dehydration.
Oral potassium and oral fluids can also be administered with the intravenous fluids
if the patient is not vomiting and their mental status is intact. During fluid rehydration,
urine output should be monitored and patients should be assessed periodically for
signs of hyponatremia and hypernatremia [125].
Diet
The benefit of a specific dietary regimen other than oral hydration has not been well
established. Adequate caloric intake during an episode of acute diarrhea facilitates
enterocyte renewal [126]. Boiled starches and cereals consisting of rice, noodles,
potatoes, wheat, and oat are generally tolerated in patients with watery diarrhea.
Crackers, bananas, yogurt, soup, and boiled vegetables may also be consumed.
Antibiotics
Empiric antibiotics should be prescribed for patients with severe acute diarrhea manifested
by symptoms of bacterial diarrhea. In this selected population of patients, antibiotics
decrease length and severity of illness [127], [128]. Additional criteria for empiric
antibiotics are fever, occult blood, numerous fecal leukocytes in the stool, abdominal
pain, more than six bowel movements in 24 hours, diarrhea lasting greater than 48
hours, and immunosuppression [129], [130]. Travelers with severe acute diarrhea are
usually infected with a bacterial pathogen and illness is shortened by antimicrobial
therapy [131], [132], [133]. Before initiation of empiric antibiotics for severe acute
diarrhea, all patients should be questioned carefully regarding their risk for C difficile
and tested for the pathogen.
Commonly recommended empiric regimens include ciprofloxacin, TMP-SMX, or erythromycin
until a specific pathogen with sensitivities is identified from stool examination
and culture [8], [9].
Symptomatic therapy
Antidiarrheal agents improve quality of life, can decrease stool frequency and stool
volume, and shorten clinical illness [134], [135]. In industrialized countries, antidiarrheal
medications are cost effective and useful in returning people to work and school.
There is controversy in their use when invasive pathogens are suspected. In patients
with high fever, sepsis, bloody diarrhea, or immunocompromised patients, avoid antimotility
medications because they can delay clearance of pathogens from the bowel, resulting
in increased tissue invasion and prolonged disease [136], [137].
In afebrile patients with nonbloody stools, antimotility agents, such as loperamide
or diphenoxylate, may be used for the symptomatic treatment of patients with acute
diarrhea. These agents work by slowing intraluminal flow of liquid, facilitating intestinal
absorption [138]. Loperamide is the drug of choice because of its safety and efficacy.
Diphenoxylate with atropine is cheaper than loperamide but has central opiate effects
and may have cholinergic side effects [139]. Both drugs may facilitate the development
of HUS in patients infected with enterohemorrhagic E coli
[140]. Patients should increase their fluid intake while taking antimotility agents
because these agents may cause fluid pooling in the intestine, and mask fluid losses.
Bismuth subsalicylate is useful for prevention or treatment of travelers' diarrhea.
It has antidiarrheal effects through an antisecretory salicylate moiety, and its antibacterial
properties make it useful as prophylaxis in travelers' diarrhea [141], [142], [143].
Compared with placebo, bismuth subsalicylate reduces number of stools by approximately
50% [144].
Attapulgite is a clay-like substance that absorbs water, creating formed stools. It
also adsorbs toxins made by bacteria and prevents toxin adherence to intestinal membranes
[145], [146]. Attapulgite is not effective in febrile bloody diarrhea and in general
is less effective than loperamide, but is a safer medication because it is not absorbed
[147].
Many drugs exert antisecretory effects through different mechanisms including inhibition
of prostaglandins, cyclic AMP, inhibition of calmodulin, and encephalinase inhibition
of chloride channels. Oral enkephalinase inhibitor (Racecadotril) is currently in
clinical trials. It is an antagonist of 5HT3 receptors and prevents degradation of
endogenous opioids (enkephalins), reducing hypersecretion of water and electrolytes
into the intestinal lumen [148], [149], [150].
Summary
Acute diarrhea is commonly caused by an infection. Severe acute diarrhea warrants
immediate medical evaluation and hospitalization. Indications for stool studies include
fever; bloody diarrhea; recent travel to an endemic area; recent antibiotics; immunosuppression;
and occupational risks, such as food handlers. Noninfectious causes include inflammatory
bowel disease, radiation enteritis, and intestinal ischemia. Management of severe
acute diarrhea includes intravenous fluid rehydration and empiric antibiotics. Use
of antidiarrheal agents is controversial when invasive pathogens are suspected.